1. Field of the Invention
The present invention generally relates to a sabot. More particularly, the present invention relates to a plastic collar used to hold a single bullet during discharge from a muzzle loading rifle.
2. Background Art
A precursor of the modern rifle was the muzzle loader. Operation of a muzzle loader required one to first pour a defined quantity of black powder into a barrel. Next, a wad, typically a piece of cloth or leather, was tamped into the barrel compacting the powder and holding it secure. Finally, a lead ball was positioned on top of the wad. In this condition, the muzzle loader was ready to be fired. A piece of flint positioned on top of a hammer would ignite the powder causing the wad and lead ball to be discharged from the barrel. Although revolutionary for its time, the muzzle loader was extremely inaccurate and had minimal strength.
With the development of rifling being formed within the barrel, dramatic increases in the accuracy of the muzzle loader were discovered. Rifling, however, also increased the difficulty of loading the barrel. Rifling a barrel entails forming a plurality of grooves that are helically positioned along the length of the bore of the barrel. The portions of the bore between the grooves are known as lands.
The principle of rifling is to produce a spin on the projectile about its longitudinal axis as the projectile is discharged through the barrel. The spin produces a gyroscopic effect on the projectile, giving the projectile greater accuracy. However, for the lead ball to engage the rifling grooves in a muzzle loader, the lead ball must have a diameter slightly larger than the inside diameter of the muzzle bore. As the ball is pressed into the bore, the lead indents into the grooves. On discharge, the ball rotates following the grooves, thereby rotating the lead ball.
Although accuracy was increased, pressing the oversized lead ball the length of the barrel was a very strenuous and time consuming task. Furthermore, although it was known that a conical shaped bullet, as opposed to a ball, would be more aero-dynamic and produce a more accurate shot, the force required to position the bullet in the barrel deformed the conical nose of the bullet. As a result, the deformed bullet would have an erratic flight path.
With the invention of self-contained cartridges, muzzle loading became obsolete for conventional military and hunting uses. Nevertheless, the muzzle loader has continued to find favor with an ever-increasing group of purists who continue to use the muzzle loader for hunting and sport shooting. Although the principle of muzzle loading has remained relatively constant, the apparatus has improved in an attempt to alleviate past problems and improve the speed, distance and accuracy of the bullet.
To alleviate some of the previous problems with loading, a sabot was designed to replace the conventional wad. A sabot is a plastic sleeve that holds the bullet during discharge. The sabot typically comprise a cylindrical body having a receiving chamber accessible at a receiving end and a base at the other end. During operation, as before, the black powder is poured into the barrel. A bullet is then positioned within the receiving chamber of the sabot. Finally, the base of the sabot is pressed down the barrel, compacting the black powder.
In prior applications, the outside diameter of the sabot is normally slightly larger than the groove to groove diameter of the bore so that as the sabot is pressed into the barrel the sabot indents into the grooves of the rifling. Accordingly, as the powder is ignited, the sabot rotates in the rifling grooves during discharge, thereby simultaneously rotating the bullet. The sabot is useful in that the receiving chamber of the sabot can be made to fit any size or shape of bullet without having to change the barrel size or decrease the amount of black powder used. This is accomplished by varying the thickness of the walls of the receiving chamber.
Although it is easier to position a plastic sabot than a lead ball, the oversized plastic sabot still requires considerable effort and time to be pressed the length of the barrel. In fact, the amount of force required to position the sabot is so great that the ramrod will often deform the nose of soft, conical, lead bullets.
An additional problem associated with plastic sabots is that as the muzzle loader is discharged, the black powder leaves a rough, gritty residue on the wall of the barrel. As the muzzle loader is continually loaded and discharged, the gritty residue scrapes a portion of the plastic off the sides of the sabot forming a plaque on the wall of the barrel. In turn, this plaque increases the difficulty of loading the sabot and detrimentally affects the accuracy of the bullet shot.
The use of conventional sabots is also inadequate when firing higher velocity bullets. Discharging high velocity bullets from conventional sabots results in disruption of the sabots and irregular flight paths of the bullets. It is theorized that the combination of the mass of the bullet and the explosion of the black powder overcomes the strength of the sabot, causing the sabot to fail within the barrel. In turn, failure of the sabot results in an uneven force being applied to the bullet, thereby affecting the bullet's trajectory.